The American film industry's transition to sound, which began in 1927 and was completed by 1930, had an immediate effect on the nation's movie theaters. The cost of installing a sound system—"wiring for sound," as it was called—could be prohibitive for the independent owner-operator of a small theater. There were competing sound systems, and each system required the purchase of new projection equipment in addition to speakers. Costs for converting theaters to sound had dropped significantly by 1929, though the investment could still run as high as seven thousand dollars for even a small theater. Good quality sound reproduction might even entail the redesigning of the auditorium itself to improve acoustics, as well as the installation of a quieter heating and cooling system. (The transition to sound thus indirectly led to an increased use of air conditioning.) On the positive side, the novelty of sound became, in the short term, a major drawing card for theaters.
Particularly from the late 1920s through the mid-1930s, the state of sound film technology required that projectionists be responsible for the audio as well as visual quality of the movies screened. Staffing of the movie theater changed as well with the introduction of sound, as talkies quickly replaced the regular live entertainment that had always been part of the moviegoing experience.
In effect, with Hollywood fully committed to the production of sound films, theater owners had no choice except to wire for sound, sell out, or close. Approximately two-thirds of the fifteen thousand theaters in the United States were wired for sound by 1930, as the new